Optical transceiver and optical transmission/reception method

Abstract

In order to suppress any reduction in the reception performance of an optical transceiver, the optical transceiver includes a light source, an optical splitter that splits the output of the light source into a first split light and a second split light, an optical modulation unit that modulates the first split light, a coherent receiver that causes the inputted received light to interfere with the second split light, and a first control unit that controls the split ratio of the optical splitter on the basis of the reception characteristic of the received light received by the coherent receiver.

The invention claimed is: 
     
       1. An optical transceiver comprising:
 a light source; 
 an optical splitter configured to split output of the light source into first split light and second split light; 
 an optical modulator configured to modulate the first split light; 
 a coherent receiver configured to cause input reception light to interfere with the second split light; and 
 a controller configured to control a splitting ratio of the optical splitter, using a reception characteristic of the reception light received by the coherent receiver and intensity of the first split light modulated by the optical modulator. 
 
     
     
       2. The transceiver according to  claim 1 , wherein the optical modulator is configured to receive a part of the first split light. 
     
     
       3. The optical transceiver according to  claim 1 , wherein the controller is configured to accept an output signal converted from a part of the first split optical signal modulated. 
     
     
       4. The optical transceiver according to  claim 1 , wherein the controller is included in a signal processor configured to analyze the reception characteristic. 
     
     
       5. The optical transceiver according to  claim 1 , further comprising a light intensity adjuster configured to adjust optical power of the first split light,
 wherein the controller is configured to instruct an amount of controlling the optical power to the light intensity adjuster. 
 
     
     
       6. The optical transceiver according to  claim 5 , wherein the light intensity adjuster is an optical attenuator, and
 wherein the controller is configured to, if transmission light power of the optical transceiver is larger than a prescribed value, control the optical attenuator in such a way that the optical power of the first split light is reduced. 
 
     
     
       7. The optical transceiver according to  claim 5 , wherein the light intensity adjuster is an optical amplifier, and
 wherein the controller is configured to control gain of the optical amplifier in such a way that the optical power of the first split light becomes a prescribed power. 
 
     
     
       8. The optical transceiver according to  claim 5 , wherein the light intensity adjuster is configured to adjust optical power of the first split light output from the optical modulator. 
     
     
       9. The optical transceiver according to  claim 5 , wherein the light intensity adjuster is configured to adjust optical power of the first split light input to the optical modulator. 
     
     
       10. A control method of an optical transceiver, the method comprising:
 splitting output of a light source into first split light and second split light; 
 modulating the first split light; 
 causing input reception light to interfere with the second split light; and 
 controlling a splitting ratio of splitting, using a reception characteristic of the reception light and intensity of the first split light modulated. 
 
     
     
       11. The control method according to  claim 10 , wherein the modulation is performed by an optical modulator configured to receive a part of the first split light. 
     
     
       12. The control method according to  claim 10 , wherein the controlling is performed by a controller configured to accept an output signal converted from a part of the first split optical signal modulated. 
     
     
       13. The control method according to  claim 10 , wherein the controlling is performed by a controller included in a signal processor configured to analyze the reception characteristic. 
     
     
       14. The control method according to  claim 10 , further comprising adjusting optical power of the first split light,
 wherein the controlling includes instructing an amount of controlling the optical power to the adjusting optical power of the first split light. 
 
     
     
       15. The control method according to  claim 14 , wherein the adjusting optical power of the first split light is performed by an optical attenuator, and
 wherein, if transmission light power of the optical transceiver is larger than a prescribed value, the optical attenuator is controlled in such a way that the optical power of the first split light is reduced. 
 
     
     
       16. The control method according to  claim 14 , wherein the adjusting optical power of the first split light is performed by an optical amplifier, and
 wherein gain of the optical amplifier is controlled in such a way that the optical power of the first split light becomes a prescribed power. 
 
     
     
       17. The control method according to  claim 14 , wherein the adjusting optical power of the first split light adjusts optical power of the first split light output from the optical modulator. 
     
     
       18. The optical transceiver according to  claim 14 , wherein the adjusting optical power of the first split light adjusts optical power of the first split light input to the optical modulator.